The present invention relates to reinforced flexible panels and to a method and means of corrugating them.
There exists a need and demand in the building and construction industry for flexible sheets of water-impermeable and insulating material with a degree of inherent strength, whereby said sheets may be self-supporting. Many known plastic sheets variously suffer from the disadvantage of being flimsy, inflammable, poor insulators and awkward to use as construction materials. It is an object of the present invention to provide improvements over the art.
There is known and sold, for instance as Sisalkraft 310, a reinforced flame retardant sheet which serves as a moisture and vapor barrier and is foil faced to provide reflective insulation. The general nature of such a known sheet in cross section is shown in FIG. 1 of the accompanying drawings, the four layers of the sheet being shown separated in exaggerated form for clarity. A fire retardant paper sheet is coated on one surface with a plastic material and on the other surface with a metal foil, a scrim of fiberglass mesh being sandwiched between the foil and paper. As will be evident, such a sheet, although fire retardant and reflective, has no inherent strength, is in no way self-supporting and is awkward to use and secure as a construction material.
It is a more specific object of the invention to provide an improvement over such known sheets.